Cervelleite, Ag4TeS, from three localities in Romania, substitution of Cu, and the occurrence of the associated phase, Ag2Cu2TeS

Abstract

Compositional and paragenetic data are reported for cervelleite, ideally Ag 4 TeS, from three new occurrences in Romania: from Upper Cretaceous skarn mineralisation at Bāiţa Bihor, Northern Apuseni Mts. and Ocna de Fier, Banat, and from Neogene hydrothermal Au-vein mineralisation at Larga, Metalliferi Mts. Cervelleite from the two skarn occurrences contains significant amounts of Cu. Together with previously published compositional data, limited solid solution from Ag 4 TeS to approximately (Ag 3 . 2 Cu 0 . 8 ) 4 TeS can be recognised. Closely associated with cervelleite in both skarn occurrences is an additional phase, Ag 2 Cu 2 TeS, which we believe is a possible new quaternary mineral in the Ag-Cu-Te-S system.